A fresher repo: https://github.com/comboy/bitcoin-elixir
Bitcoin script and protocol tools plus a full node implementation written in Elxir.
It's still work in progress, not suitable for any kind of usage. Contributions and comments are of course very much welcome, but if you want to jump in, I'd suggest to get in touch (through github issues) because all APIs are still evolving.
Project is a fork of Justin Lynn's Bitcoin-Ex which contained excellent protocol parsers and DNS peer discovery.
Opinionated interface to Bitcoin core JSON-RPC API. Currently in MVP mode: architecture is ready and stable, doesn't fully implement all of the RPC commands yet, although this would be trivial to do. Open an issue (or better yet, create a pull request) if you want to see more functionality added.